My pullet, now a 7yo hen, won best of breed at our 4H show at 8 months old. That was out of ~20 other birds, they're popular here. Whoever told you that was smoking something.
Edited to add: Seeing your pic now, she does look like she has a bit too much white in her, even in a hen that would be a tad too much. I'll post some pics of my girl up in a bit, gotta transfer them from my cam. By breeding her to a cock w/ too much red/black, you should be fine. It's not your breeders you're too worried about, it's the chicks they throw.